1. Field of the Invention
This invention relates generally to a data processing system having add-on card slots, and more particularly to a data processing system for hot inserting/removing add-on cards withtout affecting the current data processing operation.
2. Background of the Invention
Many existing data processing systems have add-on card slots to utilize add-on cards to increase/enhance performance. xe2x80x9cHot insertionxe2x80x9d is the capability to add and remove add-on devices to a data processing system while the data processing system is running and have the operating system automatically recognize the change. In a data processing system having hot-insertion capability, add-on cards can be inserted/removed into/from the data processing system while the data processing system is powered and running. Such capability is especially desirable in network data processing systems. For example, users may remove and insert add-on cards for maintenance without having to shut down the server or suspend operations.
To achieve convenient backward compatibility, no hardware changes should be required for standard add-on cards and only the add-on card drivers should need to be changed to support hot-insertion. Further, system hardware and software support should be provided for monitoring and controlling the hot insertion/removal of, for example, PCI cards. The prior art includes Compaq Computer Corporation""s implementation of PCI hot-insertion technology in its severs. A hot-insertion controller and corresponding driver for each PCI slot for monitoring and controlling the hot insertion/removal of PCI cards is utilized. Generally, the more PCI slots a data processing system has, the more hot-insertion controllers and corresponding drivers it needs, but this will increase the manufacturing costs and the complexity of the system.
What is needed therefore, is a data processing system and a method which will achieve hot-insertion without increasing the complexity of design and higher manufacturing costs. The present invention utilizes only one hot insertion controller and its corresponding driver in conjunction with a plurality of operand latches to monitor all add-on card slots and control the signal switches and power switches of the add-on card slots for hot insertion.
The present invention comprises a data processing system, having a data bus and a power supply, for hot inserting an add-on card into an add-on card slot is provided. The data processing system includes an add-on card slot having a plurality of signal lines for transmitting a first group of signals, a power switch coupled to the power supply and the add-on card slot a signal switch coupled to the data bus and the add-on card slot, and detecting means for detecting an insertion of the add-on card into the add-on card slot. The data processing system also includes driver means and control means. The driver means is responsive to the insertion of the add-on card into the add-on card slot for generating a first, second, third, and fourth instructions in sequence. The control means is responsive to the first instruction for requesting the data bus and thereafter turns on the power switch. The control means further is responsive to the second instruction for resetting the add-on card. The control means still further is responsive to the third instruction for pulling the first group of signals logic high. The control means is further responsive to the fourth instruction for requesting the data bus and thereafter turns on the signal switch.
The present invention also comprises a method for hot inserting an add-on card into an add-on card slot of a data processing system having a data bus. The add-on card slot has a plurality of signal lines for transmitting a first group of signals. The method comprises the steps of requesting an IDLE state of the data bus in response to an insertion of the add-on card into the add-on card slot; turning on power thereby supplying power to the add-on card upon granting of the data bus; resetting the add-on card; pulling the first group of signals logic high; requesting another IDLE state of the data bus; and electrically coupling the add-on card to the data bus upon granting of the data bus.